fix(signals): use Injector of rxMethod instance caller if availab…

…le (#4529)

Closes #4528

modules/signals/rxjs-interop/spec/rx-method.spec.ts

@@ -1,10 +1,17 @@
 import {
+  Component,
   createEnvironmentInjector,
   EnvironmentInjector,
+  inject,
   Injectable,
+  Injector,
+  OnInit,
   signal,
 } from '@angular/core';
 import { TestBed } from '@angular/core/testing';
+import { provideLocationMocks } from '@angular/common/testing';
+import { provideRouter } from '@angular/router';
+import { RouterTestingHarness } from '@angular/router/testing';
 import { BehaviorSubject, pipe, Subject, tap } from 'rxjs';
 import { rxMethod } from '../src';
 import { createLocalService } from '../../spec/helpers';
@@ -231,4 +238,221 @@ describe('rxMethod', () => {
     TestBed.flushEffects();
     expect(counter()).toBe(4);
   });
+
+  /**
+   * This test suite verifies that a signal or observable passed to a reactive
+   * method that is initialized at the ancestor injector level is tracked within
+   * the correct injection context and untracked at the specified time.
+   *
+   * Components use `globalSignal` or `globalObservable` from `GlobalService`
+   * and pass it to the reactive method. If the component is destroyed but
+   * signal or observable change still increases the corresponding counter,
+   * the internal effect or subscription is still active.
+   */
+  describe('with instance injector', () => {
+    @Injectable({ providedIn: 'root' })
+    class GlobalService {
+      readonly globalSignal = signal(1);
+      readonly globalObservable = new BehaviorSubject(1);
+
+      globalSignalChangeCounter = 0;
+      globalObservableChangeCounter = 0;
+
+      readonly signalMethod = rxMethod<number>(
+        tap(() => this.globalSignalChangeCounter++)
+      );
+      readonly observableMethod = rxMethod<number>(
+        tap(() => this.globalObservableChangeCounter++)
+      );
+
+      incrementSignal(): void {
+        this.globalSignal.update((value) => value + 1);
+      }
+
+      incrementObservable(): void {
+        this.globalObservable.next(this.globalObservable.value + 1);
+      }
+    }
+
+    @Component({
+      selector: 'app-without-store',
+      template: '',
+      standalone: true,
+    })
+    class WithoutStoreComponent {}
+
+    function setup(WithStoreComponent: new () => unknown): GlobalService {
+      TestBed.configureTestingModule({
+        providers: [
+          provideRouter([
+            { path: 'with-store', component: WithStoreComponent },
+            {
+              path: 'without-store',
+              component: WithoutStoreComponent,
+            },
+          ]),
+          provideLocationMocks(),
+        ],
+      });
+
+      return TestBed.inject(GlobalService);
+    }
+
+    it('tracks a signal until the component is destroyed', async () => {
+      @Component({
+        selector: 'app-with-store',
+        template: '',
+        standalone: true,
+      })
+      class WithStoreComponent {
+        store = inject(GlobalService);
+
+        constructor() {
+          this.store.signalMethod(this.store.globalSignal);
+        }
+      }
+
+      const globalService = setup(WithStoreComponent);
+      const harness = await RouterTestingHarness.create('/with-store');
+
+      expect(globalService.globalSignalChangeCounter).toBe(1);
+
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+      expect(globalService.globalSignalChangeCounter).toBe(2);
+
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+      expect(globalService.globalSignalChangeCounter).toBe(3);
+
+      await harness.navigateByUrl('/without-store');
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+
+      expect(globalService.globalSignalChangeCounter).toBe(3);
+    });
+
+    it('tracks an observable until the component is destroyed', async () => {
+      @Component({
+        selector: 'app-with-store',
+        template: '',
+        standalone: true,
+      })
+      class WithStoreComponent {
+        store = inject(GlobalService);
+
+        constructor() {
+          this.store.observableMethod(this.store.globalObservable);
+        }
+      }
+
+      const globalService = setup(WithStoreComponent);
+      const harness = await RouterTestingHarness.create('/with-store');
+
+      expect(globalService.globalObservableChangeCounter).toBe(1);
+
+      globalService.incrementObservable();
+      expect(globalService.globalObservableChangeCounter).toBe(2);
+
+      globalService.incrementObservable();
+      expect(globalService.globalObservableChangeCounter).toBe(3);
+
+      await harness.navigateByUrl('/without-store');
+      globalService.incrementObservable();
+
+      expect(globalService.globalObservableChangeCounter).toBe(3);
+    });
+
+    it('tracks a signal until the provided injector is destroyed', async () => {
+      @Component({
+        selector: 'app-with-store',
+        template: '',
+        standalone: true,
+      })
+      class WithStoreComponent implements OnInit {
+        store = inject(GlobalService);
+        injector = inject(Injector);
+
+        ngOnInit() {
+          this.store.signalMethod(this.store.globalSignal, {
+            injector: this.injector,
+          });
+        }
+      }
+
+      const globalService = setup(WithStoreComponent);
+      const harness = await RouterTestingHarness.create('/with-store');
+
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+
+      expect(globalService.globalSignalChangeCounter).toBe(2);
+
+      await harness.navigateByUrl('/without-store');
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+
+      expect(globalService.globalSignalChangeCounter).toBe(2);
+    });
+
+    it('tracks an observable until the provided injector is destroyed', async () => {
+      @Component({
+        selector: 'app-with-store',
+        template: '',
+        standalone: true,
+      })
+      class WithStoreComponent implements OnInit {
+        store = inject(GlobalService);
+        injector = inject(Injector);
+
+        ngOnInit() {
+          this.store.observableMethod(this.store.globalObservable, {
+            injector: this.injector,
+          });
+        }
+      }
+
+      const globalService = setup(WithStoreComponent);
+      const harness = await RouterTestingHarness.create('/with-store');
+
+      globalService.incrementObservable();
+
+      expect(globalService.globalObservableChangeCounter).toBe(2);
+
+      await harness.navigateByUrl('/without-store');
+      globalService.incrementObservable();
+
+      expect(globalService.globalObservableChangeCounter).toBe(2);
+    });
+
+    it('falls back to source injector when reactive method is called outside of the injection context', async () => {
+      @Component({
+        selector: 'app-with-store',
+        template: '',
+        standalone: true,
+      })
+      class WithStoreComponent implements OnInit {
+        store = inject(GlobalService);
+
+        ngOnInit() {
+          this.store.signalMethod(this.store.globalSignal);
+          this.store.observableMethod(this.store.globalObservable);
+        }
+      }
+
+      const globalService = setup(WithStoreComponent);
+      const harness = await RouterTestingHarness.create('/with-store');
+
+      expect(globalService.globalSignalChangeCounter).toBe(1);
+      expect(globalService.globalObservableChangeCounter).toBe(1);
+
+      await harness.navigateByUrl('/without-store');
+      globalService.incrementSignal();
+      TestBed.flushEffects();
+      globalService.incrementObservable();
+
+      expect(globalService.globalSignalChangeCounter).toBe(2);
+      expect(globalService.globalObservableChangeCounter).toBe(2);
+    });
+  });
 });

modules/signals/rxjs-interop/src/rx-method.ts

@@ -11,7 +11,8 @@ import {
 import { isObservable, noop, Observable, Subject, Unsubscribable } from 'rxjs';
 
 type RxMethod<Input> = ((
-  input: Input | Signal<Input> | Observable<Input>
+  input: Input | Signal<Input> | Observable<Input>,
+  config?: { injector?: Injector }
 ) => Unsubscribable) &
   Unsubscribable;
 
@@ -23,39 +24,61 @@ export function rxMethod<Input>(
     assertInInjectionContext(rxMethod);
   }
 
-  const injector = config?.injector ?? inject(Injector);
-  const destroyRef = injector.get(DestroyRef);
+  const sourceInjector = config?.injector ?? inject(Injector);
   const source$ = new Subject<Input>();
-
   const sourceSub = generator(source$).subscribe();
-  destroyRef.onDestroy(() => sourceSub.unsubscribe());
+  sourceInjector.get(DestroyRef).onDestroy(() => sourceSub.unsubscribe());
+
+  const rxMethodFn = (
+    input: Input | Signal<Input> | Observable<Input>,
+    config?: { injector?: Injector }
+  ) => {
+    if (isStatic(input)) {
+      source$.next(input);
+      return { unsubscribe: noop };
+    }
+
+    const instanceInjector =
+      config?.injector ?? getCallerInjector() ?? sourceInjector;
 
-  const rxMethodFn = (input: Input | Signal<Input> | Observable<Input>) => {
     if (isSignal(input)) {
       const watcher = effect(
         () => {
           const value = input();
           untracked(() => source$.next(value));
         },
-        { injector }
+        { injector: instanceInjector }
       );
       const instanceSub = { unsubscribe: () => watcher.destroy() };
       sourceSub.add(instanceSub);
 
       return instanceSub;
     }
 
-    if (isObservable(input)) {
-      const instanceSub = input.subscribe((value) => source$.next(value));
-      sourceSub.add(instanceSub);
+    const instanceSub = input.subscribe((value) => source$.next(value));
+    sourceSub.add(instanceSub);
 
-      return instanceSub;
+    if (instanceInjector !== sourceInjector) {
+      instanceInjector
+        .get(DestroyRef)
+        .onDestroy(() => instanceSub.unsubscribe());
     }
 
-    source$.next(input);
-    return { unsubscribe: noop };
+    return instanceSub;
   };
   rxMethodFn.unsubscribe = sourceSub.unsubscribe.bind(sourceSub);
 
   return rxMethodFn;
 }
+
+function isStatic<T>(value: T | Signal<T> | Observable<T>): value is T {
+  return !isSignal(value) && !isObservable(value);
+}
+
+function getCallerInjector(): Injector | null {
+  try {
+    return inject(Injector);
+  } catch {
+    return null;
+  }
+}